CableLabs: Full Duplex DOCSIS 3.1 speed breakthrough

Cable industry research consortium CableLabs has revealed details of a project that illustrates how DOCSIS 3.1 technology provides the basis for continued evolution of system capacities by supporting symmetric multi-Gigabit service over the cable network.

According to Belal Hamzeh, VP Wireless, R&D and Dan Rice, SVP, R&D, building on state of the art technology, ongoing DOCSIS 3.1 technology deployments have squarely set the cable industry on the path to deliver Gigabit services over HFC networks, noting that during its recent 2016 Winter Conference, CableLabs unveiled a Full Duplex DOCSIS technology which applies emerging techniques from wireless networks to achieve a breakthrough increase in the upstream speeds for DOCSIS delivered broadband service. A Full Duplex DOCSIS network is a prime example of the CableLabs 2.0 vision using its rich innovation funnel of technologies to transform the industry, they say.

“Existing technologies mostly use either Frequency Division Duplexing (FDD) or Time Division Duplexing (TDD). In FDD, upstream and downstream (or uplink and downlink in the terms of the wireless world) traffic operate separately in dedicated parts of the spectrum. In current DOCSIS network deployments, the lower part of the spectrum is dedicated for upstream traffic and the upper part of the spectrum is dedicated for downstream traffic. In TDD, the upstream and downstream traffic share the same spectrum, but take turns in using the spectrum, similar to how Wi-Fi, or DSL, operate. In Full Duplex communication, the upstream and downstream traffic use the same spectrum at the same time, doubling the efficiency of spectrum use. A DOCSIS 3.1 Full Duplex network provides the peak speeds and flexibility of TDD solutions, but one-ups both TDD and FDD with double the capacity,” they advise.

“Using a combination of Passive HFC and the self-interference cancellation and intelligent scheduling of DOCSIS 3.1 technology, CableLabs has built a solution that proves the viability of full duplex communication. Its approach significantly increases upstream data capacity in order to enable symmetric multi-Gigabit broadband data services for consumers and the enterprise. These developments are expected to yield DOCSIS 3.1 network performance of up to 10 Gbps symmetrical on 1 GHz HFC networks, with the potential for even higher performance by utilising spectrum that is currently available for future expansion above 1 GHz,” they report.

According to the pair, one of the compelling attributes of a Full Duplex DOCSIS 3.1 network for the next evolution in HFC delivery is the strong foundation DOCSIS 3.1 technology provides. “Our design and analysis shows that the existing Physical and MAC layer protocols in DOCSIS 3.1 technology can largely support this new symmetric service. The evolution to a DOCSIS 3.1 Full Duplex network is an incremental evolution of DOCSIS 3.1 technology and will support both backward compatibility and coexistence with previous generations of DOCSIS network deployments,” they confirm, adding that, if all signs remain positive, the project will transition from an innovation effort into an R&D project, open to all interested participants.

Dennis Steiger, CTO of nbn Australia, who is in the US meeting with CableLabs to discuss the arrival of this new technology, said that although it was still very early days, the arrival of Full Duplex DOCSIS 3.1 was “extremely exciting news” for nbn and “a real game-changing moment” in the ultra-fast broadband market.

“We will be working closely with CableLabs to track the development of this technology and are excited about the potential this offers for the 4 million premises that will receive their nbn services via our HFC network. Previously it was only possible to deliver multi-Gigabit symmetrical broadband if you deployed an FTTP network – but HFC is now right up there in terms of being able to deliver these kinds of speeds. We now have the pathway to deliver these ultra-fast symmetrical speeds to our HFC end-users both very cost-effectively and far more conveniently than we could if we had to deliver fibre all the way to their homes.”